The present invention relates to a door closure or fastening device for doors of ovens, in particular coke ovens, of the type including a compression spring producing the locking pressure positioned between a spring bearing or support member which is arranged on the body of the door, a locking bar that cannot be turned in relation to the door, and a locking bar support being shiftable toward the spring bearing member by a lever system, through which the locking bar can be moved away from the locking hooks.
In a door closure device of this kind, and as shown in German Pat. No. 687,175, the locking bar support consists of a pin or bolt that is guided by a locking bar, and a spring bearing, which includes a pot-shaped housing and a cover. These two parts of the spring bearing are attached to a holder on the door body by means of bolts or pins, such that the pot-shaped housing can be shifted transversely to the plane of the door on the pins. The door closure device is operated by a lever system, which is mounted on a door operating device that can be moved in front of the door. The lever system includes a plurality of rocking levers, that can be pressed through rollers mounted on their ends toward one another and/or against the face of the pin employed as the locking bar support, as well as against a pressure surface below the locking bar. The operation of these levers is effected in cooperation with two grippers that likewise belong to the lever system and can extend behind a transverse beam of the oven door.
This known door closure is associated with the disadvantages of being very expensive to construct and of requiring a large number of parts subjected to wear and bearings. Further, this known lever arrangement leads to the movement of the engagement points of the levers on the countersurface of the parts actuated by the levers. Therefore, it is necessary to provide rollers mounted on the levers for the transmission of the operating forces. Further, the known door closure must be equipped with adjusting means, in order to compensate for the manufacturing and assembly tolerances occurring both on the oven door and also on the door operating device. Even further, the adjustment of the initial tension of the spring which produces the locking force is a very complex operation.
Still further, the action of the operating forces in the form of pressure is disadvantageous in that in certain cases it may lead to twisting or other deformation of the parts of the door closure that are acted upon by such forces. Finally, the door closure can be operated only by means of the door operating machine which includes the lever system, so that an emergency operation of the door closure is practically impossible without the door operating machine. The same is true also for a simultaneous operation of a plurality of oven doors of a battery of ovens.